氮肥运筹对雹后重播受旱棉花生长特性及产量影响

Effect of nitrogen fertilizer management on the growth characteristics and yield of drought cotton after hail reseeding

【目的】研究氮肥运筹对雹后重播受旱棉花生长特性及产量影响。【方法】主区为正常蕾期灌水处理(CK),蕾期中度水分胁迫处理,副区为4种施氮比例不施氮(N_(0))、以盛铃期为界限分为(蕾期肥+花期肥)∶铃期肥3∶7(N_(37))、(蕾期肥+花期肥)∶铃期肥5∶5(N_(55))、(蕾期肥+花期肥)∶铃期肥7∶3(N_(73)),研究雹后重播受旱棉花的最佳氮肥运筹。【结果】在同一氮肥处理下,蕾期中度水分胁迫较CK处理生育进程提前,茎粗、有效果枝、倒四叶宽、双铃率以及LAI、Pn均有所降低,干物质最大积累速率及出现时间、拐点提前;干物质最大积累量、干物质向生殖器官分配比例,单株成铃数、籽棉产量有所下降,单铃重、衣分无显著差异;在同一水分处理下,铃期肥比例增加,生育进程延后,倒四叶宽增加;不同追肥比例在茎粗、有效果枝数、倒四叶宽、双铃率、LAI、Pn均优于N_(0)处理,干物质最大积累量、最大积累速率、单株结铃数、籽棉产量均高于N_(0)处理;在正常蕾期灌水处理(CK)下N_(55)处理表现最优,较N_(0)、N_(37)、N_(73)处理籽棉产量增产_(37).58%、13.89%、12.85%;在蕾期中度水分胁迫下N_(37)处理的茎粗、有效果枝、双铃率LAI、Pn优于CK处理,且增加效果显著;干物质积累量较CK处理的快速生长期缩短了1~7 d,营养器官干物质积累量、生殖器官干物质积累量平均降低了8.63%、54.83%,快速积累速率增加了49.6%,干物质最大积累量、持续时间、以及最大积累速率以N_(37)为最优且增加效果最为明显,单株结铃数、籽棉产量以N_(37)处理最高,分别比N_(0)、N_(55)、N_(73)增产57.33%、34.01%、18.35%。【结论】雹后重播受旱(蕾期中度水分胁迫)条件下,生育期追肥比例(蕾期肥+花期肥)∶铃期期3∶7时籽棉产量较CK不仅没有下降,还有所增产。棉花重播受旱下追肥比例设置为(蕾期肥+花期肥)∶铃期肥3∶7为最佳施肥比例。

【Objective】To study the effect of nitrogen fertilizer management on the growth characteristics and yield of drought-affected cotton after hail reseeding.【Methods】The main area was normal bud stage irrigation treatment(CK),bud stage moderate water stress treatment,and the sub-area was 4 kinds of nitrogen application ratios(N_(0)).The boundary was divided into:(bud stage+flowering stage).Fertilizer∶Boll stage fertilizer 3∶7(N_(37)),(bud stage+flowering stage)∶Boll stage fertilizer 5∶5(N_(55)),(bud stage+flowering stage)∶Bell stage fertilizer 7∶3(N_(73)).The purpose was to study the best nitrogen fertilizer management for the drought cotton.【Results】Under the same nitrogen fertilizer treatment,the moderate water stress at the bud stage was earlier than the CK treatment.The stem thickness,effective branches,first fourth leaf width,double boll rate,LAI and Pn were all reduced,and the maximum dry matter accumulation rate was as low as the emergence time and the turning point was advanced;the maximum accumulation of dry matter,the distribution ratio of dry matter to the reproductive organs,the number of bolls per plant and the yield of seed cotton declined,and there was no significant difference in single boll weight and lint;under the same water treatment,the boll stage when the fertilizer ratio increased,the growth process was delayed,and the width of the top four leaves increased;different topdressing ratios were better than the N_(0)treatment in terms of stem thickness,number of effective branches,width of the top four leaves,double boll rate,LAI,and Pn.The maximum dry matter accumulation rate,the number of bolls per plant,and the yield of seed cotton were all higher than those of N_(0)treatment;N_(55)treatment performed best under normal bud stage irrigation treatment(CK),which increased_(37).58%,13.89%,and 12.85%compared with N_(0),N_(37),and N_(73)treatments;Under moderate water stress in the bud stage,the stem thickness,effective shoots,double boll rate LAI and Pn of N_(37)treatment were better than CK treatment,and the increase effect was significant;the dry matter accumulation was 1-7 days shorter than the rapid growth period of CK treatment;the dry matter accumulation of vegetative organs and reproductive organs decreased by 8.63%and 54.83%on average,and the rapid accumulation rate increased by 49.6%.The maximum accumulation amount,duration and maximum accumulation rate of dry matter were optimal with N_(37)and the increase effect was most obvious.The number of single plant knot and seed cotton yield was that treated with N_(37),which increased by 57.33%,34.01%and 18.35%than N_(0),N_(55)and N_(73),respectively.【Conclusion】Under the condition of reseeding and drought(moderate water stress in bud stage)after hail,the ratio of topdressing fertilizer in growth period and fertilizer in flowering period:3∶7 in boll period did not decrease but increased the yield of seed cotton compared with CK.In the case of cotton reseeding and drought,the topdressing ratio is set to(bud stage+flowering stage)fertilizer∶boll stage fertilizer 3∶7 is the best.